Tony Judt’s dazzling, cantankerous brain is one of this city’s great treasures. Now, two years into a devastating battle with ALS, it is all he has left.

It’s a bit of a struggle to get comfortable right now,” says Tony Judt, who is seated in a book-lined office in an apartment above Washington Square. He says this in a matter-of-fact way. He has been resting a little, as he does for short spells throughout the day. The room is very warm and quiet, save for the whirring of the air pump that keeps his diaphragm functioning and his labored intake through the bi-pap valve embedded in each of his nostrils. Three large computer monitors stand adjacent to one another on a long desk. They run a looped slideshow—snapshots of Judt walking with his wife, clowning around with his children, wearing various styles of glasses (square and clunky giving way to round and sleek), sitting in a chair with an arm draped casually across its back.

Now Judt excuses himself and very patiently gives instructions on how to make sitting upright, for a time, bearable. Just a little bit forward with the legs, please. All right. Now—up—and back. His nurse, a sturdy man with a black ponytail, wrestles with the electronic knobs that control the many moving parts of his wheelchair. No—up, as far as it can go. Far as it can go. That’s right. Just a little bit down. And now back. That’s right. Judt requires the assistance of a microphone to be easily heard, and the speaker crackles with the sound of his sighs.

The disease that has paralyzed most of Judt’s body—amyotrophic lateral sclerosis, or Lou Gehrig’s disease—has reduced his voice to a hoarse whisper, though it still retains the distinctive rhythms and intonations that made it, until recently, a commanding instrument. Judt is, by common assent, one of the most eloquent and erudite public intellectuals working today—“one of the great political writers of the age,” in the judgment of the political philosopher John Gray. He presides over the Remarque Institute at New York University, where he supports research, schedules lectures, and shapes the direction of European historical studies. He has written eight books on the history of politics and ideas in Europe, and is a famously tough-minded and combative writer of essays, reviews, and op-ed pieces. All in all, he is one of the most admired and denounced thinkers living in New York City.

ALS is incurable, fatal, and little understood. It leaves its victims mentally intact. It does not obliterate sensation, and it does not inflict any pain. As Judt puts it, “You’re free to sit there quite calmly contemplating your own steady decline.” Recently, he dictated for The New York Review of Books a short essay offering his readers a glimpse into his bedroom at night. “There I lie,” he wrote, “trussed, myopic, and motionless like a modern-day mummy, alone in my corporeal prison, accompanied for the rest of the night only by my thoughts.”

He went on to invite his readers to imagine deleting their ability to move their arms and legs from various daily settings—to scratch their hand, or shift position at night—and consider the effect this would have on their morale. Morning, he wrote, brings “an occasion to communicate with the outside world and express in words, often angry words, the bottled-up irritations and frustrations of physical inanition.” By the time he refers to his “cockroachlike existence” of “humiliating helplessness,” his simple thought experiments have posed a paradox: How can a man enduring the unbelievable torment described within the essay have retained the clarity and poise to have written it?

The essay was unlike anything he had written before: an intimate view of the author’s private anguish. “I can’t remember another piece of memoiristic writing that created such waves of interest in our little pond,” says the writer and Columbia professor Todd Gitlin. It was not, however, the whole of his written output. After spending a few months absorbing the shock of his diagnosis eighteen months ago, Judt has become enormously prolific: dictating essays and opinion pieces, delivering a public lecture to a packed auditorium, and assembling material for three books, one of which—a rallying cry on behalf of a renewed social democracy—will be published next week. Consigned to a broken body but perfectly sound in mind, he has acquired something of a second presence beyond that of a historian and public intellectual—a figure whose pathos haunts the thoughts of others. “There are many days now where I find myself thinking about Tony Judt,” says Gitlin, “and I hardly even know him.”

“I use words to make sense of my life,” explains Judt. “Words can make the illness a subject I can master, and not one that one simply emotes over.” Longtime admirers believe Judt’s writing is stronger than it has ever been. “He has been able to do some of his best work,” says Robert Silvers, the editor of TheNew York Review of Books, who has assigned Judt more than 60 pieces over the years. “The pure intensity of effort and courage needed to arrive at the ability to do it is something difficult to imagine. It’s a great victory for him.”